1. Field of the Invention
The technical field of the present invention relates to a power storage device and a manufacturing method thereof.
2. Description of the Related Art
With an increase in concern for the environmental issues, energy storage devices such as secondary batteries and electric double layer capacitors used for power supply for hybrid vehicles have been actively developed. As the energy storage devices, a lithium ion battery and a lithium ion capacitor having high energy performance have attracted attention. The lithium ion battery, which is compact but can store large electricity has been already mounted on a portable information terminal such as a mobile phone or a notebook personal computer, and has helped miniaturization of products.
The secondary battery and the electric double layer capacitor have a structure in which an electrolyte is provided between a positive electrode and a negative electrode. It is known that each of the positive electrode and negative electrode includes a collector and an active material provided over the collector. For example, in a lithium ion battery, a material capable of injection and extraction of lithium ions is used in each electrode as an active material, and an electrolyte is interposed between the electrodes.
A lithium oxide and the like are known as a positive electrode active material of a lithium ion battery (see Patent Documents 1 and 2).